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Home projects

Estimate paint without guessing.

Measure a room or wall, subtract doors and windows, then account for coats, product coverage, and a practical waste allowance.

Measure the project

Coverage and waste assumptions

Door and window estimates use 21 and 15 square feet, or about 1.95 and 1.4 square meters.

Why coverage is an estimate

Paintable wall area is the wall surface minus openings. Multiple coats multiply that area, and a waste allowance helps cover roller loading, touch-ups, and small measurement differences.

Texture, porosity, application method, color changes, and the specific product can all change coverage. Use the coverage printed on the paint label when it differs from the default.

Reference: Sherwin-Williams paint guidance says a gallon typically covers about 350 to 400 square feet, depending on the surface and desired coverage.

This calculator is a planning estimate. Confirm container sizes, product coverage, surface preparation, and application instructions before purchasing.